This research will analyze the effect of age at first marriage on career development and divorce propensities. A large literature in economics, sociology, and demography has sought to explain the 35-year rise in age at first marriage in the United States. The fundamental premise behind most hypotheses for the rise in age at first marriage is that the cost of remaining single has declined over time and that individuals have responded to these lower costs by delaying marriage. However, very little research has asked why individuals should respond to a decline in the cost of remaining single at all. That is, why should an individual want to delay marriage? This research will explore two frequently cited, but virtually untested, reasons for delaying marriage: early marriage inhibits career development and early marriage increases the probability of divorce. The specific aims of this research are to: (1) describe the age-earnings profiles of individuals who marry and have children relatively early in life versus those who delay marriage and have children relatively late in life with special attention to variation across cohorts, race, gender, and educational attainment; (2) explore the role of unobserved heterogeneity that may simultaneously influence earnings and age at first marriage and birth using panel data and data on marriage and birth expectations; and (3) investigate the link between age at first marriage and the subsequent probability of divorce using marriage and birth expectations and sibling data as controls for unobserved heterogeneity. By carefully considering the role of unobserved heterogeneity in determining age at first marriage, this research will provide the foundation for future work on the overall consequences of delayed marriage in the United States, including its effects on out-of-wedlock childbearing, overall fertility, and child outcomes.